Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 22: Fokus: Conjugated Polymers
CPP 22.3: Topical Talk
Mittwoch, 25. März 2009, 10:30–11:00, ZEU 160
Influence of microstructure on transport and recombination in conjugated polymer:fullerene blend films — •Jenny Nelson1, Amy Ballantyne1, Mariano Campoy-Quiles1, Toby Ferenczi1, Jarvist Frost1, Panos Keivanides1, Ji-Seon Kim1, James Kirkpatrick1, Christian Mueller2, Donald Bradley1, James Durrant1, Paul Smith2, and Natalie Stingelin3 — 1Imperial College London, UK — 2ETH Zuerich, Switzerland — 3Queen Mary University of London, UK
The dynamics of charge carriers in conjugated polymer:small molecule blend solar cells are strongly influenced by the microstructure of the blend films. Efficient photocurrent generation appears to require, at the same time, a high degree of order in local molecular packing (benefitting charge transport and charge separation), a large interface (for charge separation) and significant phase segregation (to minimise charge recombination). In this work, we will show how a combination of spectroscopic techniques, electrical measurements and studies of phase behaviour can be used to build up a picture of the microstructure in a polymer: fullerene blend film, and to relate the microstructure to the dynamics of charge separation, transport and recombination. To interpret the results we use coarse grained models of the evolution of phase morphology and kinetic Monte Carlo models of charge transport and recombination. Finally, we demonstrate that the optimum blend composition for photocurrent generation can be related in a rational way to the phase behaviour of the binary system and in particular to the self-organising tendency of the component materials.